Disc drives are common data storage devices. A typical disc drive includes a housing that encloses a variety of disc drive components. The components include one or more rotating discs having data surfaces that are coated with a medium for storage of digital information in a plurality of circular, concentric data tracks. The discs are mounted on a spindle motor that causes the discs to spin and the data surfaces of the discs to pass under respective aerodynamic bearing disc head sliders. The sliders carry transducers, which write information to and read information from the data surfaces of the discs. The slider and transducer are often together referred to as a “head.” An actuator mechanism moves the sliders from track to track across the surfaces of the discs under control of electronic circuitry. The actuator mechanism includes a track accessing arm and a suspension for each slider. The suspension includes a load beam and a gimbal. The load beam provides a preload force, which forces the slider toward the disc surface. The gimbal is positioned between the slider and the load beam, or is integrated in the load beam, to provide a resilient connection that allows the slider to pitch and roll while following the topography of the disc.
The suspension generates the preload force through a preload bend in the load beam, which becomes elastically deformed when the suspension is loaded into the disc drive. The preload bend is typically formed near a proximal mounting section of the load beam, which is adjacent the track accessing arm. The load beam has a relatively rigid portion, which transfers the preload force from the elastically deformed preload bend to the slider. The rigid portion is typically made by forming stiffening rails or flanges along the longitudinal edges of the suspension.
During operation, the suspension can experience off-track vibrations that can interfere with the proper positioning of the head by causing non-repeatable run-out (NRRO) and other read and write problems or limit track density. As suspensions become increasingly smaller in order to accommodate high density storage systems and to reduce weight, the resonance frequencies of the suspension have increased. Therefore, it is common to provide a damper on the suspension for damping the off-track vibrations. It is desirable for the damper to cover a large surface area of the suspension and be located along areas having the highest strain energies from vibrational modes, such as bending, torsional and sway modes. Current suspension designs have the highest strain energies along the preload bend. However, the preload bend region of the suspension typically has relatively narrow beams that have relatively small surface areas on which to attach a damper, which could limit its effectiveness.
Also, placing the damper along the preload bend would be difficult and costly to manufacture because of low tolerances in the preload bend region and the non-planar surface on which the damper would be attached. In addition, due to the small surface area relative to the current size constraints of typical damper material, the damper material may project from the sides of the suspension and thereby expose its damping layer to the internal environment of the disc drive. The exposed damping layer can contaminate as well as interfere with the performance of the disc drive. As a result, dampers are often placed along the rigid portion of the suspension, between the stiffening rails where there is a large planar surface on which to attach the damper, but with less damping effectiveness.
Embodiments of the present invention provide solutions to these and/or other problems and offer other advantages over the prior art.